But many had the cheapest versions of Apple's iThings, the ones that only come with 16GB of storage. Between photos, texts, music, apps, games, and videos, there were plenty of people who didn't have enough free space to install iOS 8, so they stuck with iOS 7. As a result, iOS 8 adoption was much slower than it was with iOS 7 the year before.

(Yes, you could still update your iPhone or iPad by plugging it into iTunes no matter how much free space you had, but clearly not many people did that.)

Tuesday's update to iOS 8 means you need far less free storage to get the software. We saw at least one person on Twitter who was able to update his iPad with just 445 MB free. But we've seen others say some devices still require up to 3GB of free storage.

It's just another example that proves Apple made a mistake making the entry-level iPhone 6 come with just 16GB of storage. That's simply not enough to store all the stuff you need on your phone and ensure you're able to easily get the newest version of iOS when it comes out.

Meanwhile, most premium non-Apple smartphones come with at least 32GB of storage.

It's nice that the mid-tier iPhone 6 comes with 64GB of storage now (versus 32GB in earlier iPhone models), but that essentially forces people to spend an extra $100 they ordinarily wouldn't need to spend. In fact, Apple could profit $3 billion by making people buy the more expensive iPhones, simply because the cheapest model doesn't have enough storage.